[testing] Add some unit-test for pioneer3dx robot

Cover issue #245
Don't link it with the build for moment, as it is completely broken.
[builder] Detach all the wheels

Previously, we miss the CasterWheel on the pioneer3dx
[builder] Make Pioneer3DX inherit from WheeledRobot
Try to improve the situation for wheeled robots with only 3 wheels

It improves a bit stuff (understand that it does not finish prematurely
with some exception), but it still does not work well (v=1.0, w=0.0)
does not lead to straight line ...
[camera] No self.__class__ in super()

Which can lead to recursive call
[sensor] kinect